Parties that your friend throws — general party etiquette dictates that you should invite said friend to a party at later date featuring free beer

Free beer is often, but not always is paired with free booze. Please note that free booze is to be regarded with a degree of suspicion as it is easier to spike than beer from a keg or a can. Also, do not accept free beer in a cup from strangers, rather fill the beer from the keg yourself.

As the saying goes, there's no such thing as a free lunch; it would follow that there are some disadvantages to free beer as well.

Disadvantages of free beer:

Free beer is often shitty beer — see Natty Ice (Well Why would we want to spend good money for people we don't know or care about?)

Fungal Fact!

Free Beer (like all other beer) is made from yeast. Yeast are budding fungi that excrete alcohol under anaerobic conditions. An interesting UC Davis fact is that Emil M. Mrak (as in Mrak hall) was a food science professor who studied yeasts. He has two species named for him: Williopsis mrakii and Zygosaccharomyces mrakii. - The Saprophyte